Satellites are important links for communication between stations at different locations throughout the world, particularly for mobile communication stations. For a satellite system to give worldwide coverage, a network or constellation of satellites is desirable.
Each satellite within such a satellite constellation has one or more directional antennas producing a coverage pattern on Earth referred to as the "footprint" of the satellite antenna. When multiple polar orbiting satellites are used, the satellites converge towards the poles and antenna footprints begin to overlap.
Where the antenna footprint is made up of separate "cells" in which individual communication is to take place, certain cells overlap. When cells from one satellite overlap cells from another satellite, the cells may be turned off as part of a cell management plan to prevent interference between cells of the same channels.
Individual cells generally have limited capacity for communication traffic. A cell's capacity is generally based on the amount of traffic channels available for communication. In satellite communication systems where the satellites move with respect to the surface of the Earth, individual cells may pass over high population density areas having a high demand for communication services. There may be situations where the demand for communication services within an individual cell may exceed the cell's capacity. When this occurs, ongoing communications may unfortunately, be terminated (i.e., calls may be dropped) and/or new subscriber units requesting access to the communication system may be denied access and unable to make a call.
Thus what is needed is a method and apparatus for managing loading in a cellular communication system that reduces or prevents cell traffic overload. What is also needed is a method and apparatus of encouraging subscriber units within overloaded cells to seek service from other overlapping cells that are not overloaded.